As discussed in U.S. Pat. No. 4,151,763 the entire disclosure of which is hereby incorporated by reference, the most common type of adjustable wrench includes a first fixed jaw and a second jaw that is movable with respect to the fixed jaw by a rotatable screw in order to control the spaced relationship between engagement surfaces of the jaws. Some disadvantages of such a wrench include: (1) the time involved manipulation required to move the wrench by screw rotation between fully opened and fully closed positions; (2) difficulty in maintaining the screw at a fixed position without any slight rotation that enlarges the spaced relationship between the jaw surfaces and permits rounding of the corners of a nut or bolt head being torqued; and (3) the necessary positioning of the rotatable screw adjacent the jaws and the consequent relatively wide width thereof which makes it somewhat inconvenient or impossible for the wrench to be utilized in certain confined areas.
The aforementioned U.S. Pat. No. 4,151,763 discloses an open-end and box-end wrench that is: (1) easily and quickly adjusted between its fully opened and fully closed positions at each end thereof; (2) fixed in any adjusted position thereof by a lock mechanism to prevent opening movement that can round corners of a nut or bolt head being torqued; and (3) useable in relatively confined areas due to the construction thereof which permits a relatively narrow width of the jaws at the open-end of the wrench.